I completely understand the concern you have. The safety of our beloved fury friends has to be the top priority whenever we do anything for them. That being said, I wouldn't have posted this instructable if there was a chance that this leash would break. Paracord is extremely strong and lasts forever. If it ever did start to wear down in any way, I would notice that. It is also important to say that as pet owners, we do need to take our own common sense into consideration. I wouldn't expect anyone to just "Take my word" for how strong this is. I would expect someone to look at this project, or any project, and use their common sense as to whether they feel it is safe for their pets or not. Thank you very much for bringing that up.